Asymmetric Synthesis of Highly Substituted β‐Lactones through Oxidative Carbene Catalysis with LiCl as Cooperative Lewis Acid

Abstract The reaction of enals with β‐diketones, β‐ketoesters, and malonates bearing a β‐oxyalkyl substituent at the α‐position by oxidative NHC catalysis to provide highly substituted β‐lactones is described. Reactions occur with excellent diastereo‐ and enantioselectivity. The organo cascade comprises two CC bond formations and one CO bond formation. Up to four contiguous stereogenic centers including two fully substituted stereocenters are formed in the cascade.